Composite gear and method of making same



April 26; 19 27.

L. T. FREDERICK COMPOSITE GEAR AND METHOD OF MAKING SAME Filed Auz. 1923 v Z0227 Tfiederz'c% All Patented Apr. 26,, 1927.

UNITED STATES PATENT OFFICE.

LOUIS T. FREDERICK, OF VALPARAISO, INDIANA, ASSIGNOB TO FIBBOQ INSULATION COMPANY, OF VALYARAISO, INDIANA, A CORIOBA'IION OI INDIANA.

COMPOSITE GEAR AND METHOD or MAKING sum.

Application. filed August 13, 1923. Serial No. 657,181.

My invention relates to composite gears and methods of making the same. Gears of this nature are frequently referred to as fiber gears and consist of fibrous material and a binding substance such as aphenol condensation product of the general character set forth in Baekeland Patent 1,160,364. Laminated gears consisting of a woven fabric consolidated and held in compressed state by means of a phenol con-, densation product are not broadly new, being shown, forexample, in Conrad Patent 1,167,743; but in that patent the-gear wheel isof uniform thickness from center to circumference. It is desirable in many cases especially in gears of the larger sizes or in gears of either large or small sizes in which the available room on the shaft is limited, and also in those cases where it is desired to lighten the gear-to reduce the thickness of the central portion of the gear, thus producing a rim section of the fullwidth or thickness of the gear and a central or web sectionwhich is thinner. Various methods have been attempted fior producing such gears having a reduced web section. Ac-

cording to one method the surplus material is machined away, but this method is expensive by reason of the waste of the material which is removed. According to another method, rings of fabric have been employed and these have been inter-leaved or alternated with the peripheral portion of complete discs, the rings thickening the rim portion and building up the gears at this part. This method, however, is defective in that the sheets of fabric are distorted during manufacture, and it is impossible, commercially speaking at least, to produce a gear wheel in which the cross section will be uniform. If it is not uniform the gear when rotating will tend to run out of true.

The gear bein unbalanced will have a tendency to wob 1e and this will result in excessive wear at certain points, thus rendering the gear noisy and short-lived. The object of my invention is to produce a gear having, a web section of reduced thickness but which will lend itself to ready manufacture and will make it possible under commercial conditions to produce a gear in which the cross section on any given plane will be symmetrical'and the sections on all diametral. planes'will be the same.

In carrying out my process I produce the web section from a set of sheets of layers all lying in parallel planes and produce the thickened rim section by adding, outside oi the web section, a plurality of rings arranged" in. parallel planes and held under compression by suitable binding means, preferably a phenol condensation product. According to onedevelopment of my method the web section layeis and the ring layers are plaqed in a mold provided with means for producing differential pressures so that the rim section will receive an aggregate compression greater than the. web section which contains fewer layers.

1 accomplish my object in the manner i..- lustrated in the accompanying drawings, in which- Figure l is a view of a suitable type of mold shown in diametral section. In this figure the plungers or dies are shown in initial position, that is, at the beginning of their compressive action.

Figure 2 is similar to Figure l but shows the mold closed upthat is, with the dies in final position.

Figure 3 is a diametral section of a gear blank produced according to my process.

Figure 4 is a view partly in diametral section of a gear produced according to the process. v

Figure 5 is a side view of the gear.

Figure 6 is a fragmentary view illustrating more or less diagrammatically the arrangement of the component parts of the gear. I

Like numerals denote like parts throughout the several views. Y.

I will describe the method in connection with a mold and press especially adapted for it. This consists of an outer cylindrical shell i hav' a lower ring plunger 2 and an upper ring p unger or die 3. Fitting within these plungers are cylindrical plungers 4 and 5. Plungers 4 and 5 are chambered to receive helical compressionsprings 6. The. parts 1 and 2 normally rest upon any suitable platen or platform 7, and the pressure is obtained from the platen 1 0 of any suitable type of press. WVhen operating upon phenol condensation products or binders of similar characters it is desirable to heat the platen in any appropriate manner, for example by steam pipes 12.

In charging the mold I first place in it a plurality of rings 14 of fibrous material, for

lower spring ti will rest upon the supportingplatform. he parts are so proportioned that the upper surface of die a will be above the level of the upper surface of ring 2. I

' then lower the upper ring 3 into position in the shell 1 and then lower the plunger 5 into position. The upper compression spring '6 is put in place, whereupon the mold is charged ready for the descent of the platen 10 of the press. The parts will then present the appearance shown in Figure 1, the ring 3 projecting above the upper surface of the upper plunger 5, and the upper spring-6 contacting the lower surface of the platen. The mold is now ready to be-closed up in the sense of being subjected to ressure.

As the platen 10 descen s itexerts pressure upon all surfaces of the contents of the mold. The pressure upon the rim portions formed by the rings 14: and 18 and interven ing portion of the discs 16 is a direct unyielding pressurewhile the pressure of the plungers 4, 5 upon the web section is a yielding pressure, as the springs 6 intervene between the stationary support'and the platen 10. As the platen descends the-springs yield and finally permit the lower plunger 4 to reach the lower support and the platen 10 to reach the upper plunger 5. The platen continues to descend until the mold is entirely closed and the parts occupy the positions shown in Figure 2. A convenient method for limiting the descent ofthe plunger is to so proportion the height of the shell 1 that the correct pressure will be attained when the platen seats upon the top of the shell as shown in Figure 2.

The parts are permitted to remain in this condition under heat until the fabric and its binder have been firmly consolidated, compressed and hardened, after which the plungers and the gear blank will be removed and the press thus prepared for another charge. When the compressing and'hardening is complete the gear blank will present the appearance in cross section shown in Figure 3. The rings 14: and 18 form the rim section and the central portion of the discs 16 form the web section.

The blank is now ready to be machined and the machining may be accomplished in the usual way. For example, the gear-teeth 4 18 may be generated by the bobbing process.

Ordinarily it will also be necessary to cut out a central aperture 20 tor accommodating the shaft on which the ear is to be mounted.

It will be observed t at as a result of my method there is no waste of material; also "tendency for the gear section to lack unlformity. Onthe contrary not only wilLa given diametral section be symmetrical, but all vdiametral sections will be alike. The mold instead of having a tendency to throw the planes out of true will have a tendency to keep them true. The result is that the gear will be perfectly balanced about its central' axis and will alwa s run true. This will prevent it from bemgbnoisy and will increase its life- In Figure 6, I have illustrated diagrammatically theappearance of the component parts of the finished gear, the layers of woven fabric being impregnated with the binder. The appearance of the parts in this figure is exaggerated in order to render the construction more apparent.

Having thus described my invention what I claim as new and desire to secureby Letters Patent is 1. The process of making gears having webs of reduced thiclmess, consisting in assembling flatwise a plurality of circular layers of woven fabric of the full diameter of the gear in all directions, and a plurality of duoe a greater a gregate reduction of thickness in the rim t an in the web portion.

2. The process of making composite gears having a web of reduced thickness, the process consisting in assembling in parallel planes a plurality of layers of woven fabric, the outer layers consisting of'rings co-extensive with the rim section and the inner layers extending also inward toward the center to form'the web section, saturating the layers in a binder capable of hardening under heat, and compressing the rim por-* tion andthe web portion separately to prevent distortion of the fabrics from their true layers in a binder capable of hardening under heat, and compressing the rim portion andthe web portion separately but siinsv multaneously, and finally bringing the two pressures to approximately the same degree of intensit per unit area, the pressures being exerted in a direction perpendicular to the plane of the gear.

4. The process of making gears having websfof reduced thickness, consistin in assembling a plurality of circular iscs of. woven fabric in arallel planes, superposing on both sides said discs rings of woven fabric arranged in parallel planes and hav ing outer diameters of substantially the same I outer diameter as the discs, impregnating the rings and layers with a phenolic binder capable of hardening under heat, heating said rings and layers, exerting pressure thereon normal to their surfaces, and confining said rings and layers circumferentially, the heating and pressing occurrin 'simul taneously, and the rim portion-of t e gear blank receiving a greater total compression than the web portion.

, 5.-The process of making gears having webs of reduced-thickness, consistin in assembling a plurality of circular iscs of woven fabric in parallelplanes, superposing on both sides of said discs rings of woven fabric arran ed in parallel planes and having outer same outer diameter as the discs, impregnating the rings and layers with a phenolic binder capable of hardening under heat, heating sald rings and layers, exerting pressure thereon normal to their surfaces, and confining said rings and layers circumferentially d the rings at their internal diameters.

In witness whereof, I have hereunto subscribed my name.

LOUIS T. FREDERICK.

lameters of substantially the 

